New bike, having problems shifting boardman shifting

stevetaylor20

HI guys, i bought a boardman full carbon limited 2013 model with shimano 105's. Now I think this bike is really good I like it, but the problem is that 80% of the time it's fine, but the other 20 I find that the gear change of the back smaller 4 cogs, sometimes going up, or down, it can take 2 or sometimes up to 6 seconds to change, and sometimes it doesn't change, you just hear it rattle a bit and then clicking the lever again it will change gear. The odd thing is that the guy at halfords says he's test ridden it and he isn't getting this same problem, but I do???

Any advice would be great. I'm taking it for a long ride tomorrow and the halfords guy, who seems pretty good to be fair to him, says he'll rebuild the gearing sections of the bike again, and last resort give me another bike, even though he isn't able to replicate the problem.

Am i doing something wrong?! I'm pedalling when changing gear so putting pressure, I've tried one click gear changes with quick clicks as such, i've tried ones where I wait half a second with the click down or even a second depressing the click...

Thanks!
Steve

smoggysteve

Sounds like the cable isnt tight enough. If it indexes fine in the higher range but not the lower it could be cable tension.

mattv

Could also be a bent hanger or the cable wrong side of the clamp bolt on the mech.

halfround

Sounds like a cable problem. Friction somewhere between inner cable and outer , as it is new bike cables might not have been lubed or it could be an outer cable was damaged when cut. I would pull the inner cable out feeling for resistance as you go.

cougie

When you change - keep pedalling but ease back on the pressure on the pedals.

And looking at the bike from the back - are the jockey wheels lining up perfectly underneath the sprocket the chain is meant to be on ? It sounds like they're fractionally out and if you turn the cable adjuster on the rear mech you can see the mech moving over slightly. Only do this a fraction or you'll mess it all up.

stevetaylor20

Thanks for the replies.

I am fairly new to road bikes, and shimano 105. I took the bike out for a longer ride yesterday and kept trying to change my style of gear change. I feel like i'm going mad because i've managed to stop the problem in how I change gear but i don't think this is correct or normal.

So before when i pushed the large silver lever on the right to the left, to move onto a large cog at the back, I pushed it until it clicked and then let it back in the normal position okay, this is when it gave me hassle much of the time. NOW i've been pushing it to the left and when I hear the click I go a little further and then push back to the original position and it seems to work fine.

Am I mad or something or is this normal? I thought that, like on some standard handle bar gears I could push a ever util I hear a click and then let go.The smaller lever I push to the left and when that clicks it works fine, so going down to smaller cogs on the back cassette works fine.

THis would explain why the bike mechanic at halfords could not replicate the problem, and I have heard that 105 on boardman are slightly less responsive that gearing on a smae spec Specialized.